/*
 * Copyright (c) 2007-2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: ExsltBase.java,v 1.1.2.1 2005/08/01 02:08:51 jeffsuttor Exp $
 */
package com.sun.org.apache.xalan.internal.lib;

import com.sun.org.apache.xml.internal.dtm.ref.DTMNodeProxy;

import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/**
 * The base class for some EXSLT extension classes.
 * It contains common utility methods to be used by the sub-classes.
 */
public abstract class ExsltBase {
    /**
     * Return the string value of a Node
     *
     * @param n The Node.
     * @return The string value of the Node
     */
    protected static String toString(Node n) {
        if (n instanceof DTMNodeProxy)
            return ((DTMNodeProxy) n).getStringValue();
        else {
            String value = n.getNodeValue();
            if (value == null) {
                NodeList nodelist = n.getChildNodes();
                StringBuffer buf = new StringBuffer();
                for (int i = 0; i < nodelist.getLength(); i++) {
                    Node childNode = nodelist.item(i);
                    buf.append(toString(childNode));
                }
                return buf.toString();
            } else
                return value;
        }
    }

    /**
     * Convert the string value of a Node to a number.
     * Return NaN if the string is not a valid number.
     *
     * @param n The Node.
     * @return The number value of the Node
     */
    protected static double toNumber(Node n) {
        double d = 0.0;
        String str = toString(n);
        try {
            d = Double.valueOf(str).doubleValue();
        } catch (NumberFormatException e) {
            d = Double.NaN;
        }
        return d;
    }
}
